1. Technical Field
The disclosure relates to an image reading apparatus that corrects skew of an original document.
2. Description of the Related Art
In the related art, an image reading apparatus that transports an original document, which is loaded on an original document loaded stand (paper feeding tray), one by one to an original document transport path and outputs the original document to an original document output (paper output tray) after an image formed on the original document is read by an image reader disposed in the original document transport path is known.
Such an image reading apparatus corrects a skew state (skew angle) of the original document transported to the image reader using skew correcting means to ensure that original document reading processing is precisely performed by the image reader. For example, as written in Japanese Patent Unexamined Publication No. 10-35949, an active type of skew correcting means that corrects skew while transporting an original document with the original document being pinched is used as the skew correcting means in many cases.
The active type of skew correcting means is configured of a pair of two skew rollers (resist rollers) on the right and the left that is provided at the same position in a transporting direction of an original document. Each of the pair of two skew rollers is driven by separate motors. Then, the skew correcting means corrects a skew state of the original document by changing (that is, causing a transporting speed difference between the pair of two skew rollers to occur) the transporting speed of one of the pair of skew rollers according to the skew angle of the original document while the pair of two skew rollers transports the original document with the original document being pinched therebetween.
However, there is a problem of a case where only one of the pair of two skew rollers can nip the original document or skew of the original document cannot be accurately corrected for a cause such as an excessively large skew amount of the original document, depending on the size and skew state of the original document. When it is attempted to forcibly correct the skew in a case where the skew of an original document cannot be accurately corrected, the skew amount of the original document might rather become greater or the original document might be creased.